Mid Surface Extraction

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Overcoming the Barriers Imposed by

GeometrySpaceClaim Empowers CAE Analysts

July 2011

A CIMdata Report


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Overcoming the Barriers Imposed by GeometrySpaceClaim Empowers CAE Analysts

July 2011

Produced by

CIMdata, Inc.

http://www.CIMdata.com

CIMdata, Inc.3909 Research Park Drive, Ann Arbor, Michigan 48108

Tel: +1 (734) 6689922 Fax: +1 (734) 6681957CIMdata is a Registered Trademark of CIMdata, Inc.

Copyright 2011 by CIMdata, Inc. All rights reserved.


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Removing Geometry Barriers for CAE A CIMdata White Paper Page 1

Overcoming the Barriers Imposed by GeometrySpaceClaim Empowers CAE Analysts

CAE analysts often face the burden of poor quality and over-detailed geometric

models in preparing finite element meshing for analysis. However, end users ofSpaceClaim Engineer testify that the application is making a valued impact to

alleviate these barriers. To surmount those problems, a solution must be able to

import an extensive range of CAD model formats found in the industry and alsosupport an intuitive user interface that is easy to learn for non-CAD experts.

SpaceClaim boasts a positive record in each case in the opinion of their

customers. McCormick Stevenson, an engineering services company, finds that

SpaceClaim serves as a great arbiter of geometry and boasts, anything can beimported. The broad appeal of SpaceClaim Engineer as a tool for CAE analysts

is further touted by Stig Staghj Knudsen, a naval architect and CFD expert from

Ramboll Group A/S in Denmark. For them, SpaceClaim cleans up CAD models in

new ways not previously available saving a lot of product development time in theprocess.

1.IntroductionDuring the product development process, CAE analysis

offers developers an important opportunity to validate and

improve product reliability and quality. However, analysts

are often thwarted in their attempts to respond with timely

simulation results due to the burden of poor quality and

over-detailed geometric models. In order to properly mesh

the models for finite element analysis, a CAE analyst faces

the necessity to first resolve topological inaccuracies suchas gaps and small sliver surfaces in the geometry. The

analyst must then simplify the model by de-featuring the

geometric detail by removing things such as small holes,

slots, and rounds that design has added for final

manufacturing.

It is essential to meshing that a model

be watertight by eliminating any gaps

in its geometry. These holes or flaws

are often formed by mismatched

vertices or edges between solid model

faces created by importing CAD

models generated with loosetolerances or by approximations done

during CAD data translations. The

existence of gaps in the model can

easily disrupt the execution of

building a finite element mesh on the

model. Small sliver surfaces are often

generated when intersecting surfaces

and adding fillets to freeform shape models, and they must

be removed to avoid over complicated meshing. In addition,

CAE analysts based on their individual judgment will

remove geometric details, which were added to support

manufacturing by the designers, so as to further unburden

the meshing algorithm.

The extent of the challenge imposed by these two barriers is

corroborated in previous CPDA/CIMdata research. A study

on CAE Model Clean Up across numerous industry

verticals indicated that seventy-five percent of CAE

analysts interviewed faced the need to correct model errors.

In addition, eighty-eight percent in the study faced the need

to de-feature their models.

These concerns are further compounded by yet another

barrier that many CAE analysts face in dealing with

Figure 1A Detailed Model and Its De-Featured Variant


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Page 2 A CIMdata White Paper Geometry Barriers for CAE

geometric modelsthe broad array of possible geometric

data formats they must process. Many product developers

assert today that product development is a multi-CAD

endeavor. Whether the analyst serves a product

manufacturing company working with diverse supply chain

partners or represents a member of an outsource service

company doing analysis for a range of clients, the CAEanalyst must be ready to accept CAD models in a wide

range of proprietary and industry-standard formats. They

require tools that can uniformly deal with the challenge.

2.A Geometry SimplificationSolution

Recently, many firms are turning to SpaceClaim

Corporation for a solution.1 The company has positioned

their product, SpaceClaim Engineer, as a leader in 3D direct

modeling for rapid concept design and geometry

manipulation. To succeed in this role, a product must beable to import the extensive range of CAD model formats

found in the industry and offer an

intuitive user interface that is easy to

learn for non-CAD experts. SpaceClaim

boasts a positive record in each case, as

testified to by their customers.

McCormick Stevenson Corporation is a

mechanical engineering services firm

for the defense and aerospace industries

headquartered in Clearwater, Florida.2 It

specializes in mechanical packaging

and integration of electronic systems

used in harsh military environments.

The companys President, Noel

McCormick, reflects on the state of the

technology: In my experience, without

adequate simplification to the model,

the finite element iterative process can

go wildly out of control from a man-

hours standpoint. Mr. McCormick

continues, For years CAD vendors

have told a story that developers can use

the same geometry for analysis that they

use for design. In our experience, that

has never been true. He notes that oncean analyst receives a model, it takes time to prepare the data

and perform the actual simulation. The CAD design model,

1 For information on SpaceClaim Corporation and the SpaceClaimEngineer product, see www.spaceclaim.com.2 For information on McCormick Stevenson Corporation and theirservices, see www.mccst.com.

however, continues to progress and the model data sets

evolve quickly out of synch. For that reason alone any

recommended changes to the model from the CAE analyst

are communicated verbally.

McCormick Stevenson chose SpaceClaim Engineer for

their CAE analysts. After admitting to an initial hesitation

because SpaceClaim Engineer is not a traditionalparametric, history-based modeling application, Noel notes

they recognized that once a CAE analyst makes a change to

the model in preparation for analysis, It is no longer design

geometry. So moving it to SpaceClaim is a non-issue.

Further, he indicates that while de-featuring holes is not

critical in their typical models, they will mid-surface parts

wherever they can within an assembly, and then de-feature

unnecessary rounds. His assessment: SpaceClaim, with

their selection tools, makes that very easy. He continues,

We have also created geometry without any hesitation. No

training was necessary. Given that we are a consulting firm,

SpaceClaim offers us potential benefits because it is a great

arbiter of geometry. We can import anything into itonce

it is there, the design potential is obvious.

The broad appeal of SpaceClaim Engineer as a tool forCAE analysts is further touted by Stig Staghj Knudsen, a

naval architect and CFD expert from Ramboll Group A/S,

an engineering, design, and consultancy company

headquartered in Denmark.3 In a similar circumstance to

3 For information on Ramboll Group A/S and their services, seewww.ramboll.com.

Figure 2SpaceClaim Allows Removal of Non-Critical

Features to Facilitate Meshing


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Removing Geometry Barriers for CAE A CIMdata Report Page 3

that experienced by McCormick Stevenson, Mr. Knudsennotes that Ramboll, as a large contractor, gets data from a

number of industries, all of which use different CAD

software. He also reflects on the varied quality of the data

they receive. In just over the past year and a half, they have

selected SpaceClaim as their tool of choice for handling

disparate imported CAD data and preparing those models

for analysis.

Mr. Knudsen offers, We used to redraw things from

scratch. With SpaceClaim we have the ability to clean up

CAD in ways we did not have before and it has saved us a

lot of time. He speaks to one example of a client supplying

a large model and drawings and Rambolls ability to

prepare the model and analyze it within one week using

SpaceClaim, whereas he estimates it would have previously

taken three weeks. He notes, We get a lot of different

geometries and we dont want to waste a lot of time on

geometry. Often on very large CAD models with extensive

manufacturing detail, we use SpaceClaims de-featuring.

They have a lot of good tools to do bothfix errors and de-

feature, especially for industrial products.

Mr. Knudsen highlights a special point that underscores

their use of SpaceClaimthe fact that there is no one

simple solution to prepare a CAD model for simulation. He

notes that, Different tools are needed to prepare the

models. There is no easy answer as to which one to use.The last fix you used may not be the correct one for the

next problem. With SpaceClaim we can always find a

solution.

It rapidly becomes apparent that an overriding requirement

for any tool that attempts to facilitate the preparation of

CAD models for meshing and simulation done by a CAE

analyst is that it not only have the necessary

functional capabilities, but it must also be

intuitive and easy to use. Often, however, those

attributes are difficult to define and articulate.

Yet SpaceClaim has captured much of the

essence of these requirements as validated by

its customers, including Martin Schagerlind,Simulation Engineer at Vicura in Sweden.4

Vicura is an engineering company specializing

in driveline technology that originated in early

2011 from General Motors Powertrain and

Saab Automobile Powertrain AB. He notes

that with his first look at SpaceClaim he was

impressed with its ease of use. Now that he

has chosen SpaceClaim for his work he

confirms that the application is very

efficient.

Mr. Schagerlind notes that overall the power

and flexibility in SpaceClaim allows model

clean up five times faster than functions found in the

meshing tool set they use. Prior to having the CAE analyst

clean up the model, changes had to be requested from the

designer, leading to delays. He also noted that customer

communications have improved by using SpaceClaims

ability to do cross-section renderings.

3.Summary and ConcludingRemarks

The reduction of the product development cycle while

improving product quality and reliability remains a strategic

goal in all manufacturing companies. The CAE analyst

relies on an iterative cycle of model, clean up, mesh, and

analysis to make recommendations for product

improvement. The tools they use directly impact their

productivity. In the CAE analyst world, SpaceClaim is

making a valuable impact as testified to by its users.

SpaceClaim is helping them overcome the barriers imposed

by model geometry.

Research for this paper was supported by SpaceClaim

Corporation.

About CIMdataCIMdata, a leading independent worldwide firm, providesstrategic management consulting to maximize an

enterprises ability to design and deliver innovative

4 For information on Vicura and its products and services, seewww.vicura.se.

Figure 3Once Imported into ANSYS the SpaceClaim Model is Analyzed with

Reduced Computational Time Due to Its Simplification


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Page 4 A CIMdata White Paper Geometry Barriers for CAE

products and services through the application of Product

Lifecycle Management (PLM) solutions. Since its founding

more than 25 years ago, CIMdata has delivered world-class

knowledge, expertise, and best-practice methods on PLM

solutions. These solutions incorporate both business

processes and a wide-ranging set of PLM enabling

technologies.CIMdata works with both industrial organizations and

suppliers of technologies and services seeking competitive

advantage in the global economy. CIMdata helps industrial

organizations establish effective PLM strategies, assists in

the identification of requirements and selection of PLM

technologies, helps organizations optimize their operational

structure and processes to implement solutions, and assists

in the deployment of these solutions. For PLM solution

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strategies, delivers worldwide market information and

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and marketing teams, as well as overall support at all stages

of business and product programs to make them optimally

effective in their markets.

In addition to consulting, CIMdata conducts research,

provides PLM-focused subscription services, and produces

several commercial publications. The company also

provides industry education through PLM certificationprograms, seminars, and conferences worldwide. CIMdata

serves clients around the world from offices in North

America, Europe, and Asia Pacific.

To learn more about CIMdatas services, visit our website

at www.CIMdata.com or contact CIMdata at: 3909

Research Park Drive, Ann Arbor, MI 48108, USA. Tel: +1

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